David's solution is the correct way to go for this case, but you can use array
for this and sometimes it does come in handy:
So, the changes required are:
- Your second column should have been
l
eft aligned, not r
ight aligned.
- You need to eliminate the inter column spacing using
@{}
, and use &{}=
to get the proper math spacing around the equal signs.
- You should use
\exp
instead of exp
as that is an operator and not a variable.
- Perhaps use
\cdot
instead of .
(unless the lower dot notation is something I am not familiar with).
As David Carlisle commented, this formulas are displayed in the cramped \textstyle
. If you desire the \displaystyle
you need to add \displaystyle
where it is needed (in this case the second line) to obtain:
Or, if you include the array
pacakge then you can include the >{\displaystyle}
style to the column specification (as illustrated in last part of MWE).
Code:
\documentclass{article}
\usepackage{amsmath}
\usepackage{array}
\begin{document}\noindent
Without \verb|\displaystyle|:
\begin{equation}
\begin{array}{l@{}l}
\mathcal{L}^{-1}\left\{f(d)\right\}
&{}= \mathcal{L}^{-1}\left\{f_1(\delta) \cdot f_2(\delta)\right\} \\
&{}= \exp(mt) \star \left\{\frac{l}{2\sqrt{\pi t^3}} \exp(-l^2/{4t})\right\} \\
&{}= F_1 * F_2
\end{array}
\end{equation}
With \verb|\displaystyle|:
\begin{equation}
\begin{array}{l@{}l}
\mathcal{L}^{-1}\left\{f(d)\right\}
&{}= \mathcal{L}^{-1}\left\{f_1(\delta) \cdot f_2(\delta)\right\} \\
&{}= \displaystyle\exp(mt) \star \left\{\frac{l}{2\sqrt{\pi t^3}} \exp(-l^2/{4t})\right\} \\
&{}= F_1 * F_2
\end{array}
\end{equation}
With \verb|\displaystyle| and \verb|array| package:
\begin{equation}
\begin{array}{l@{}>{\displaystyle}l}
\mathcal{L}^{-1}\left\{f(d)\right\}
&{}= \mathcal{L}^{-1}\left\{f_1(\delta) \cdot f_2(\delta)\right\} \\
&{}= \exp(mt) \star \left\{\frac{l}{2\sqrt{\pi t^3}} \exp(-l^2/{4t})\right\} \\
&{}= F_1 * F_2
\end{array}
\end{equation}
\end{document}
You can eliminate the need for using &{}=
by burying that in the array
column spec:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\begin{array}{l@{{}={}}l}
\mathcal{L}^{-1}\left\{f(d)\right\}
& \mathcal{L}^{-1}\left\{f_1(\delta).f_2(\delta)\right\} \\
& \exp(mt) \star \left\{\frac{l}{2\sqrt{\pi t^3}} \exp(-l^2/{4t})\right\} \\
& F_1 * F_2
\end{array}
\end{equation}
\end{document}